73 lines
1.6 KiB
Markdown
73 lines
1.6 KiB
Markdown
# The compiler
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The compiler is the program that takes your THP code and converts it
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into something that the computer can run (in this case, PHP code).
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The compiler reads your code and tries to understand it.
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When it can't understand some part, it will ask you to clarify what
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you meant, with an error.
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## Compile time vs runtime
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Compile time is when you build your program.
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Runtime is when you run your program.
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To make an analogy with cars, compile time would be the factory,
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while runtime would be using the finished car.
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The compiler is very strict. If it finds any errors during compile time
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it will refuse to build the program.
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### Compile time errors
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Compile time errors are errors that happen while the compiler is
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building your program. In the car analogy, a compile error would happen
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if there's an error in the "blueprint"
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### Runtime errors
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These are errors that happen to the built program, or in this case,
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the finished car. It would be like the car blowing up while on the highway.
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To minimize the amount of runtime errors the compiler tries to catch them all
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during compile time. It's better if it fails in the factory than in the
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real world.
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## The compiler and datatypes
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The first measure the compiler takes is to check that all the datatypes
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match. If an operation requires a number, you can't just give it a string.
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For example, if we wanted to add a number to a string, we would get an
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error:
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```thp
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50 + "hello" // Error: The `+` operator expects two Numbers,
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// but an String was found.
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```
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This way, we can assure that many errors are avoided (since it doesn't
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really make sense to add a number to a text).
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